Goji berry: health benefits or marketing hype?

Posted on Mon, 11 Jul 11

The popularity of goji berry as a dietary supplement has grown rapidly as a result of efficient marketing, but do the health claims match the evidence?

Goji (Lycium barbarum) has been used in traditional Chinese medicine for thousands of years and is described in ancient texts as having anti-aging properties, nourishing the eyes and improving male fertility. More recently Goji has been show to have anti-oxidant, anti-diabetic, neuroprotective, and aphrodisiac type properties in experimental studies (1).

Human clinical studies on Goji are however yet confirm its therapeutic potential and a recent scientific review concluded that there is little data to support the marketing claims that Goji is a “cure-all” or a miraculous supplement for well-being and longevity (2).

Evidence for Goji benefits

To date only a few studies have assessed clinical effects of Goji berry. The first studied the effects of Goji berry juice in healthy adults over 14 days (3). It was found that Goji “increased ratings for energy level, athletic performance, quality of sleep, ease of awakening, ability to focus on activities, mental acuity, calmness, and feelings of health, contentment, and happiness” compared to placebo. Goji also significantly reduced fatigue and stress, and improved regularity of gastrointestinal function.

Another study set out to see if Goji juice could improve immunity and wellbeing in older adults (4). After 30 days of drinking Goji juice daily there was a significant increased in several measures of immune function as well as improvements in feelings of general well-being including fatigue, sleep and short-term memory.

Goji is rich in zeaxanthin an antioxidant which has benefits for eye health and may explain the traditional use of Goji for "nourishing the eyes." Human studies have shown that Goji consumption increases zeaxanthin levels and has antioxidant effects (5-7). To investigate the eye benefits of Goji a group of elderly subjects took Goji (in a milk-based drink) or placebo for 90 days (8). Supplementation with Goji increased plasma zeaxanthin and antioxidant levels and protected eye health.

Like many other berries Goji appears a healthy addition to your diet and may have unique health benefits, however more research is needed.

How much goji to take?

The safety of goji is well established from its long traditional use as a food and medicine and no adverse reactions have ever been reported. Typical doses used traditionally and in clinical studies are 120 ml of juice or 15 grams a day of dried berries which have been historically used in cooking or brewed as a tea.

Sources:

1. Braun L, Cohen M. Herbs and Natural Supplements an Evidence Based Guide. 3^rd edition. Elsievier Publishing, Australia. 2010.

2. Potterat O. Goji (Lycium barbarum and L. chinense): Phytochemistry, pharmacology and safety in the perspective of traditional uses and recent popularity. Planta Med. 2010 Jan;76(1):7-19

3. Amagase H, Nance DM. A randomized, double-blind, placebo-controlled, clinical  study of the general effects of a standardized Lycium barbarum (Goji) Juice, GoChi. J Altern Complement Med. 2008 May;14(4):403-12.

4. Amagase H, Sun B, Nance DM. Immunomodulatory effects of a standardized Lycium  barbarum fruit juice in Chinese older healthy human subjects. J Med Food. 2009 Oct;12(5):1159-65.

5. Cheng CY, et al. Fasting plasma zeaxanthin response to Fructus barbarum L. (wolfberry; Kei Tze) in a food-based human supplementation trial. Br J Nutr. 2005 Jan;93(1):123-30.

6. Amagase H, Sun B, Borek C. Lycium barbarum (goji) juice improves in vivo antioxidant biomarkers in serum of healthy adults. Nutr Res. 2009 Jan;29(1):19-25.

7. Benzie IF, et al Enhanced bioavailability of zeaxanthin in a milk-based formulation of wolfberry (Gou Qi Zi; Fructus barbarum L.). Br J Nutr. 2006 Jul;96(1):154-60.

8. Bucheli P, et al. Goji berry effects on macular characteristics and plasma antioxidant levels. Optom Vis Sci.  2011 Feb;88(2):257-62.